This sixth cinematic outing for the young wizard and Chosen One begins with storm clouds over London and the flashing around of lethal black typhoons that initially threaten to visit retribution on City bankers (a worthy aim), but instead finish up wrecking the Millennium Bridge (a bad show). These darting creatures are followers of Lord Voldemort, called Death Eaters, and something like Armageddon is approaching. Which is why Dumbledore turns up on Surbiton station to whisk Harry away from an impending assignation after his brief encounter with a good-looking black waitress at the platform cafe. He takes him to meet Horace Slughorn (Jim Broadbent), who is to be Hogwarts's new Professor of Potions. Horace taught the young Voldemort before he went to the bad, and Harry's job is to extract from him buried memories of what happened way back when. Slughorn has the film's best prop - an hourglass in which the sand moves more slowly when the ambient conversation is going well.

The film's plot is oddly wispy, the mood intentionally darker, the tone solemn and ominous, the jokes, such as they are, much broader and the special effects state-of-the-art. There is also an expectation that the audience will bring with it a knowledge of both the regular characters and the lore that surrounds them. Newcomers and those with short memories will be baffled.

But while the very future of Hogwarts and its beloved headmaster appears to be under threat, the pupils are largely concerned with amorous adventures. Ron Weasley is pursued by Lavender Brown, Luna Lovegood chases Harry, who is perpetually on the point of kissing Ginny, while a neglected Hermione petulantly sulks. Indeed, the movie might well have been called "Harry Potter and the Raging Hormones". The combination of puppy love, witchcraft and the public school ethos suggests a film that might have come about in 1939, had MGM decided to conflate three of its then-current projects: Love Finds Andy Hardy, Goodbye, Mr Chips, and The Wizard of Oz

I have no doubt that fans of the Potter novels and films are going to have a grand time with this handsome, meandering, overlong movie. But wouldn't it be a good idea if JK Rowling insisted that, what with women becoming increasingly important in the narrative, there should be a female director for one of the remaining movies? I'd love to see what happened when Harry Potter met Sally Potter. Fake orgasms in the Hogwarts's dining hall perhaps?

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